Retinal stem cells show promise

10/26/2004

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A study showing the potential ability of retinal stem cells (RSCs) to treat human retinal diseases includes two Miami University researchers among its authors. Katia Del Rio-Tsonis, assistant professor of zoology, and Jason Spence, doctoral student in zoology, are among eight scientists in the United States, Canada and Switzerland who collaborated on the work.

Their article, Facile isolation and the characterization of human retinal stem cells, is the first report on the successful identification and isolation of human RSCs and is published in the Proceedings of the National Academy of Sciences this week (Oct. 25).

The researchers show that parts of a human eye have stem cells that proliferate, easily integrate into the retina and become most cell types of the neural retina. Also, they found that human retinal stem cells proliferate much faster in culture than human brain stem cells.

Although many more studies have to be done over several years, there is the potential for these retinal stem cells one day to be used to replace diseased/damaged retinal cells in people, says Del Rio-Tsonis.

Researchers placed cells from various parts of the human eye into different growth factor solutions. Retinal stem cells multiplied and were counted. In Del Rio-Tsonis lab, adult human retinal stem cells were transplanted into embryonic chick eyes. These cells not only migrated to the right place in the retina but displayed traits specific to different retinal neurons. The Canadian team transplanted adult RSCs into 1-day-old mouse eyes (when photoreceptors would normally be developing.) The RSCs behaved similarly.

Another finding is that cells from infant eyes acted similarly to cells from 70-year old human eyes, suggesting the retinal stem cell population is maintained from birth to old age, say the researchers.

A next step for the researchers is to determine if these newly integrated RSCs make connections with the existing neurons of the retina and back to the brain.

In August, Del Rio-Tsonis received Miamis Distinguished Scholar Award for a junior faculty member who has demonstrated great potential as a scholar. Her research has focused on the cellular and molecular events that take place during lens and retina regeneration and has been funded by the National Eye Institute and National Institute on Aging of the National Institutes of Health.

Stem cells are defined as cells that can self-renew and can produce many different cell types. They are identified by how they respond to their environment.